Please do not use Yeastar products, we had lot of bad experience and we have lost lots of money. Their service is very bad most of praise of product is their internal marketing techniques...
Their products is cheap and saves money initially ... but thats all... nothing works after that. The staff who can understnad little bit of English dont want to know your problems other than more orders and the staff who dont know english just dont want to work. So you end up loosing time, money and even business.